Tipping paper and cigarette using the same

ABSTRACT

The vented filter cigarette is produced by combining a filter having a highly air-permeable circumferential surface and a tipping paper having a plurality of pores. The tipping paper has an embossment in the area of the pores formed therein. The embossment serves to create a slight gap between the tipping paper and the circumferential surface of the filter, by which the tightness therebetween is loosened. Thus, the filter ventilation is increased, and the variation in the degree of the ventilation can be reduced.

This application is a continuation of U.S. patent application Ser. No.07/946,342, filed Nov. 9, 1992, now abandoned.

FIELD OF THE INVENTION

The present invention relates to a tipping paper used for a cigarette,with which the variation in the amount of air flow from the ventedfilter (filter ventilation) can be reduced, and to a cigarette usingsuch a tipping paper.

DESCRIPTION OF THE PRIOR ART

A conventional cigarette filter is made of a fiber filter material suchas cellulose diacetate wrapped by a plug wrap paper to form acylindrical shape. A tipping paper is used for connecting the filter rodand a tobacco rod. Recently, vented filters each made by combining anair-permeable plug wrap paper and a tipping paper having pores orperforations formed by means of static electricity, laser, etc. witheach other, are widely used to reduce the yield of smoke effusingthrough the filter rod by allowing air to enter through the periphery ofthe filter. With the vented filter having the above-described structure,dilution air drawn into the filter is inhaled into the smoker's mouthfrom the outer portion of the mouth end face of the filter, whereastobacco smoke is inhaled into the mouth from the center portion of themouth end face.

However, the conventional vented filter cigarette generally entails theproblem of a large variation in filter ventilation even though thefilter material, plug wrap paper, and tipping paper of the cigarette arethe same, respectively. Since the filter ventilation and the amount ofsmoke inhaled are strongly correlated, the variation of the filterventilation should be suppressed as much as possible.

The present invention has been proposed to solve the above-describedproblem, and the purpose thereof is to provide a cigarette which cansurely control its filter ventilation.

SUMMARY OF THE INVENTION

In order to achieve the above-mentioned purpose, the authors of thepresent invention researched intensively about the variation in filterventilation of the vented filter cigarettes. The inventors conducted avariety of tests on the filter ventilation, the following results wereobtained. The degree of the variation is correlated to the tightnessbetween the plug wrap paper (or the circumference surface of the filter,in the case where no plug wrap paper is used) and the tipping paper,rather than the variation in permeability of the materials. Depending onthe degree of the tightness, the ventilation area of the plug wrap paperthrough which the dilution air passes differs from one product toanother. As a result, the filter ventilation cannot be uniformlycontrolled even if the same material is used.

In consideration of the above results of the research, the inventorsfurther carried out a number of tests, and discovered that the filterventilation can be increased, and the variation therein can be reducedby separating vent zone of the tipping paper from the plug wrap paper ofthe filter by means of an embossment formed around the vent zone of thetipping paper.

According to the first aspect of the invention, there is provided atipping paper to be used in combination with a filter having a highlypermeable circumferential surface to produce a vented filter cigarette,the tipping paper includes a plurality of pores or perforations, and anembossment formed in the region including the vent zone.

Further, according to the second aspect of the invention, there isprovided a vented filter cigarette produced by combining a filter havinga highly permeable circumferential surface and a tipping paper having aplurality of pores or perforations, the vented filter cigarette havingan embossment on the tipping paper in the region including the ventzone.

The present invention is characterized by the above-described structurein which the embossment provides a slight gap between the tipping paperand the circumferential surface of the filter around the area includingthe vent zone. With this gap, the tightness between the tipping paperand the circumferential surface of the filter is loosened, therebyincreasing ventilation of air from the vented portion of the filter, anddecreasing the variation in the filter ventilation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic development view of a tipping paper and part of acigarette according to an embodiment of the invention;

FIG. 2 is a schematic diagram showing part of a tipping paper accordingto the invention, having another pattern of embossment;

FIG. 3 is a schematic diagram showing part of a tipping paper accordingto the invention, having another pattern of embossment;

FIG. 4 is a schematic diagram showing part of a tipping paper accordingto the invention, having another pattern of embossment;

FIG. 5 is a schematic diagram showing an enlarged view of the embossmentof the tipping paper shown in FIG. 1; and

FIG. 6 is a schematic development view of a tipping paper and part of acigarette according to another embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 is a schematic development view of a tipping paper and part of acigarette according to an embodiment of the invention. As shown in thisfigure, a cigarette 10 comprises a tobacco rod 12 and a filter 14. Thefilter 14 is made of a fiber filter material such as cellulose diacetatewrapped by a plug wrap paper 18. Further, a tipping paper 16 is used toconnect the filter 14 and the tobacco rod 12 with each other. Thetipping paper 16 is secured to the plug wrap paper 18 and the tobaccorod 12 by the conventional use of glue. Such a conventional use of glueis illustrated in the publication RECENT ADVANCES IN TOBACCO SCIENCE,Vol. 13, page 85 which is hereby incorporated by reference for purposesof illustrating the state of the art.

The cigarette 10 is of a vented filter type, and employs a highlypermeable plug wrap paper 18 having a Coresta permeability of 1000 ormore, for the purpose of the reduction of the yield of smoke flowing outof the mouth end of the filter. Further, the tipping paper 16 of thecigarette has a number of ventilation pores or perforations 22 formed onthe paper in one or plural rows along the circumferential direction. Itshould be noted that all the types of filter cigarette products do notalways employ plug wrap papers. The pores or perforations 22 of thetipping paper 16 can be made by a known technique, for example, theelectrostatic method, or the laser method. With the cigarette 10 of thistype, dilution air is inhaled into the smoker's mouth from the outerportion of the mouth end face of the filter, and tobacco smoke from thecenter portion thereof.

A grid-patterned embossment 24 is provided on the tipping paper 16 alongthe row of the pores 22. More specifically, the embossment 24 is printedin the band-like region located such that the pores 22 are arranged inthe imaginary center line of the region, by means of, for example, aknurling tool. Thus, the embossment 24 provides ruggedness in the entirearea of the band-like region including the pores 22. This ruggednessapparently increases the thickness of the tipping paper in the area ofthe pores 22 by about 100-500 μm, which was measured by the Z-axisreading device of a 2.5 dimension CNC coordinate measurement apparatus,μ-STAFF (product of NIKON, trademark).

In the cigarette having the above-described structure according to thepresent invention, the embossment 24 serves to create a slight gapbetween the tipping paper 16 and the plug wrap paper 18, and loosens thetightness between the members 16 and 18, increasing the air permeabilityof the combination of the pores 22 and the plug wrap paper 18. Further,the embossment 24 also serves to reduce the variation in the airpermeability. Consequently, the filter ventilation is increased, and thevariation in the filter ventilation is also reduced.

The width of the embossment 24 should be at least 1 mm on each side ofthe pores 22 made in line. If the distance from the pore line to the endof the embossment is less than 1 mm, it is difficult to create a gapsufficiently between the pores 22 and the plug wrap paper 18 of thefilter 14. Further, the glue which secures the tipping paper 16 to theplug wrap paper 18 is not provided in an annular region having apredetermined width which corresponds to or covers the pores 22. Aventilation area of the plug wrap paper 18 is formed in the annularregion.

It is possible to form the embossment 24 in almost the entire surface ofthe tipping paper 16, or the embossment 24 can be formed only on thefilter end side of the tipping paper up to the end, as can be seen inFIG. 6. The above-mentioned cases are advantageous since such tippingpapers 16 rarely stick to the smoker's lips.

The height of the configuration of the pattern of the embossment 24should preferably be in a range of 0.05-1.0 mm. If the height exceedsthis upper limit, a problem in cigarette making can occur, whereas ifthe height is lower than this lower limit, the above-described effect ofthe embossment 24 cannot be obtained to a sufficient level.

It is preferable that the embossment 24 should be disposed such that thesurface thereof brought into direct contact with the pattern press diefaces inward. With structure in which the contact surface faces inward,the pores 22 can be separated sufficiently from the plug wrap paper 18.In the case of the contrary case, or, if the contact surface facesoutward, the effect of the embossment is slightly lessened as comparedto the former case.

The pattern of the embossment 24 is not limited to the pattern of therhombic grid-like grooves shown in FIG. 1, an enlarged portion of whichshown in FIG. 5 as an embossment 28, but the embossment may be formedinto a variety of patterns. Some of the basic examples are shown inFIGS. 2-4. FIG. 2 depicts an embossment 25 having a pattern in whichgrooves are arranged parallel with the line of the pores 22. FIG. 3depicts an embossment 26 having a pattern in which grooves are arrangedperpendicular to the line of the pores 22. FIG. 4 depicts an embossment27 having a pattern of a square grid.

Using cigarettes employing these examples, the following experimentswere conducted.

EXPERIMENT 1

By use of the tipping papers embossed in different patterns around theventilating pores as described above, and the other regular members,cigarette samples B (having the pattern shown in FIG. 2, where L=6 mm),C (that of FIG. 3), and D (that of FIG. 4) were prepared. For the sakeof comparison, a cigarette sample A having no embossment provided wasalso prepared. The conditions of each sample other than the pattern ofembossment, for example, the material, the production method, etc., werecommon unless so specified in the table exhibiting the results of thetest. Each cigarette had a length of 84 mm, a filter length of 25 mm, acircumference of 25 mm, and a draw resistance of the tobacco rod of 80mm H₂ O.

Ten samples were prepared for each type of cigarette, and mounted to aventilation meter so as to measure the filter ventilation of each of thesamples. The results were as shown in Table 1. In this table, the airpermeability of the tipping paper and plug wrap paper is indicated bythe Coresta unit. Further, reference symbol X is an average of thedegree of filter ventilation (%), reference symbol σ is a standarddeviation thereof, and reference symbol CV is a variation coefficientexpressed by the following equation.

    CV=(σ/X)×100 (%)

                  TABLE 1                                                         ______________________________________                                        Material/Permeability (Coresta)                                               Tipping paper  300    300       600  600                                      Plug wrap paper                                                                             2000   10000     2000 10000                                     Sample/Filter ventilation                                                     A       X         8.1    17.1    17.7 29.4                                            σ   2.7    2.5     5.4  3.3                                             CV        33.3   14.7    30.5 11.6                                    B       X         15.9   24.3    25.6 37.7                                            σ   3.3    3.4     2.8  3.8                                             CV        20.7   14.0    10.9 10.1                                    C       X         16.8   23.0    --   --                                              σ   3.9    2.1     --   --                                              CV        23.1   9.3     --   --                                      D       X         22.4   30.0    --   --                                              σ   4.9    2.9     --   --                                              CV        21.8   9.6     --   --                                      ______________________________________                                    

As can be seen in Table 1, it was confirmed by this experiment that thesamples B, C, D each exhibited an increased filter ventilation, and areduced variation therein, as compared to the sample A having noembossment formed.

EXPERIMENT 2

By use of the tipping papers having the embossment of the pattern shownin FIG. 5 formed around the ventilating pores, and the other regularmembers, cigarette samples F (where L=6 mm, the surface, which had beenbrought into contact with the pattern press die, facing inward), and G(where L=6, the surface, which had been brought into contact with thepattern press die, facing outward) were prepared. For the sake ofcomparison, a cigarette sample E having no embossment provided was alsoprepared. The conditions of each sample other than the pattern ofembossment, for example, the material, the production method, etc., werecommon unless so specified in the table exhibiting the results of thetest. Each cigarette had a length of 84 mm, a filter length of 25 mm,and a circumference of 25 mm. The material of the filter was acetate 2.2Y/40.000, the tobacco rod used was a commercially available tobaccoblend, and the width of the unglued zone between the tipping paper andthe plug wrap paper was 9 mm.

100 samples were prepared for each type of cigarette, and mounted to aventilation meter so as measure the filter ventilation of each of thesamples. The results were as shown in Table 2. In this table, the airpermeability of the tipping paper and plug wrap paper is indicated bythe Coresta unit. Further, reference symbol X is an average of thedegree of filter ventilation (%), reference symbol σ is a standarddeviation thereof, and reference symbol CV is a variation coefficientexpressed by the following equation.

    CV=(σ/X)×100 (%)

                  TABLE 2                                                         ______________________________________                                        Material/Permeability (Coresta)                                               Tipping paper                                                                              300    300     600  600  1200  1200                              Plug wrap paper                                                                           2000   10000   2000 10000 2000 10000                              Sample/Filter ventilation                                                     E      X        22.1   28.3  35.1 45.1  40.9 57.50                                   σ  2.26   2.96  2.86 3.70  3.12 4.64                                    CV       10.22  10.45 8.14 8.20  7.62 8.06                             F      X        25.7   33.8  43.6 56.4  51.1 68.6                                    σ  2.54   2.68  2.48 2.90  2.98 3.36                                    CV       9.88   7.92  5.69 5.14  5.83 4.89                             G      X        --     --    40.5 51.40 --   --                                      σ  --     --    2.69 2.92  --   --                                      CV       --     --    6.65 5.68  --   --                               ______________________________________                                    

As can be seen in Table 2, it was confirmed by this experiment that thesamples F and G each exhibit an increased filter ventilation, and adecreased variation therein, as compared to the sample E having noembossment formed. Further, the results indicate that the sample Gexhibits a slightly less filter ventilation and a slightly morevariation in filter ventilation than the sample F; therefore it wasconfirmed that the embossment exhibits a more enhanced effect in thecase where the surface brought into contact with the pattern press dieis used as the inner side of the tipping paper, than in the other case.

INDUSTRIAL APPLICABILITY

According to the present invention, an embossment is provided around thevent zone formed in the tipping paper. By use of the tipping paperhaving such a structure, not only the filter ventilation of a cigarettecan be increased, but also the variation in the degree of theventilation can be reduced. Consequently, the filter ventilation of thecigarette can be appropriately controlled, thereby providing a desiredsmoke yield of the cigarette.

Further, in the case where the embossment is formed in almost the entiresurface of the tipping paper, the tipping paper does not stick to thesmoker's lips easily, providing the smoker with comfortable smoking.

We claim:
 1. A vented filter cigarette comprising:a filter having afiber filter material and a permeable plug wrap paper wrapping the fiberfilter material, the plug wrap paper having a Coresta permeability of1000 or more so as to have a high and substantially uniform permeabilityoverall; a tobacco rod; and tipping paper, having a plurality of pores,connecting the filter and the tobacco rod, the tipping paper beingarranged not to reach an end of the tobacco rod which is to be lit;wherein said permeable plug wrap paper has a ventilation area whichfaces said pores and through which dilution air from the pores passes,wherein an embossment is formed on the tipping paper in a regionincluding said pores in order to loosen tightness between the tippingpaper and the plug wrap paper in said ventilation area to control filterventilation of the cigarette, and wherein said embossment is arrangedonly around the pores so as not to reach either end of the tippingpaper.
 2. The cigarette according to claim 1, wherein said embossment isformed in a region having a width of 1 mm or more on either side of thepores.
 3. The cigarette according to claim 2, wherein said embossmenthas a depth ranging from 0.05 to 1.0 mm.
 4. The cigarette according toclaim 2, wherein said embossment is formed by a pattern press die, and asurface of said embossment having contacted the pattern press die facessaid filter.
 5. The cigarette according to claim 2, wherein saidembossment has grooves of a grid-pattern.
 6. The cigarette according toclaim 2, wherein said pores constitute a row, and said embossment hasgrooves of a pattern parallel to the row of said pores.
 7. The cigaretteaccording to claim 2, wherein said pores constitute a row, and saidembossment has grooves of a pattern perpendicular to the row of saidpores.